Fix for PasswordlessEmailRequest passing literal NULL no client_secret was provided

Author: kailash-b

src/Auth0.AuthenticationApi/AuthenticationApiClient.cs

@@ -395,7 +395,8 @@ public Task<PasswordlessEmailResponse> StartPasswordlessEmailFlowAsync(Passwordl
             }
             else
             {
-                body.client_secret = request.ClientSecret;
+                if (!string.IsNullOrEmpty(request.ClientSecret))
+                    body.client_secret = request.ClientSecret;
             }
 
             return connection.SendAsync<PasswordlessEmailResponse>(

tests/Auth0.AuthenticationApi.IntegrationTests/PasswordlessTests.cs

@@ -1,19 +1,21 @@
-using Auth0.AuthenticationApi.Models;
-using Auth0.Tests.Shared;
-using FluentAssertions;
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
 using System.Net;
 using System.Net.Http;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Web;
+
+using FluentAssertions;
 using Xunit;
 using Moq;
 using Moq.Protected;
 using Newtonsoft.Json;
 
+using Auth0.AuthenticationApi.Models;
+using Auth0.Tests.Shared;
+
 namespace Auth0.AuthenticationApi.IntegrationTests
 {
     public class PasswordlessTests : TestBase
@@ -95,6 +97,29 @@ public async Task Can_launch_email_code_flow()
             response.EmailVerified.Should().NotBeNull();
         }
 
+        [SkippableFact]
+        public async Task Can_launch_email_code_flow_for_SPA()
+        {
+            Skip.If(string.IsNullOrEmpty(email), "AUTH0_PASSWORDLESSDEMO_EMAIL not set");
+
+            var request = new PasswordlessEmailRequest
+            {
+                ClientId = "Qpnq5llXeWEn1o1iLYNQSr3zFI1YPg3K",
+                Email = email,
+                Type = PasswordlessEmailRequestType.Code,
+                AuthenticationParameters = new Dictionary<string, object>
+                {
+                    ["audience"] = "settings.Audience",
+                    ["scope"] = "openid profile email offline_access",
+                }
+            };
+            var response = await authenticationApiClient.StartPasswordlessEmailFlowAsync(request);
+            response.Should().NotBeNull();
+            response.Email.Should().Be(request.Email);
+            response.Id.Should().NotBeNullOrEmpty();
+            response.EmailVerified.Should().NotBeNull();
+        }
+
         [SkippableFact]
         public async Task Can_launch_sms_flow()
         {